Motor vehicles are increasingly fitted with electric fans providing their air conditioning. These electric fans comprise in particular a motor driving a wheel associated with a cooling means.
These electric fans are controlled by a control device supported by an electronic circuit board implemented on a printed circuit. When the motor is operating, the electronic circuit board is acted upon and the printed circuit gives off heat.
To discharge this heat, it is already known practice to use the air flow passing through the wheel (providing the ventilation) to cool the printed circuit board. So doing, this air flow enters into contact not only with the radiator (usually made of aluminum) of the control device but also with the various electronic components present on the printed circuit. Such cooling is usually satisfactory, but when the ambient air blown over the printed circuit is polluted, the electric connections of the various components, even the components themselves, risk being damaged by the polluted air.
Thus in a salty environment (a saline maritime atmosphere) and/or an environment polluted by particles of mud, dust, snow, ice, etc, these particles are found on the printed circuit board and damage the components and/or their connections.